Efforts to get women controlled HIV prevention tools have once again suffered a setback following the release of final results from a 4 year study that that sought to determine the safety and effectiveness of two antiretroviral (ARV)-based HIV prevention approaches in women.
Speaking to a select team of journalists in the trial countries of Uganda, Zimbabwe and South Africa via teleconference on Monday afternoon, the lead researchers announced that none of the three products - tenofovir gel, oral tenofovir and oral Truvada proved to be effective among the women enrolled in the VOICE study.
“These results are disappointing but it is clear that daily use (gel or tablet) is not the right approach for women like those in VOICE (mostly young and unmarried); adherence was very low,” said Dr Jeanne Marrazzo of the University of Washington who was due to present the results at the ongoing 20th Conference on Retroviruses and Opportunistic Infections (CROI) in Atlanta, USA.
According to the study results, drug was detected in less than a third of blood samples from women who were assigned to use either Truvada or oral tenofovir and in less than a quarter of samples from women designated to use gel.
Carried out at 15 sites in the three countries involving a total of 5,029 women, the VOICE study was designed in a way that saw participants enrolled either in groups taking a daily tablet (Tenofovir or Truvada) in what was called oral Pre-exposure prophylaxis (PrEP) or in the group that used the Tenofovir vaginal gel daily.
Testing of the daily use of Tenofovir tablets and Tenofovir gel was stopped in September 2011 and November 2011 respectively after routine independent reviews of data showed while both products were safe, they were not effective in guarding women against HIV infection. However, it was not known until yesterday that all the three products including Truvada whose testing was allowed to continue through the end of the study failed because women simply failed to use the products on a daily basis as per the study design.
In explaining the results, the Microbicides Trials Network which designed the study observed in a statement that although the VOICE outcome was disappointing, VOICE has proved that daily use of a product – whether a vaginal gel or an oral tablet – is not the right HIV prevention approach for African women like those in VOICE, who were predominately young and unmarried.
Further analysis of the results showed that compared to older, married participants, single women under the age of 25 were least likely to use their assigned products and most likely to acquire HIV. With incidence of HIV in young women at some trial sites in South Africa exceeding 10 percent, a rate considerably higher than expected, the researchers concluded that this underscores the gravity of the epidemic in a population that continues to be among the most vulnerable to HIV infection.
Meanwhile these results especially in the case of daily Truvada - which was found to be effective in other trials in other populations, and was subsequently approved last year by the U.S. Food and Drug Administration (FDA) for HIV prevention with consistent use- underscore the significance of adherence to usage.
This, according to MTN, also means that “data from VOICE will be important as the World Health Organization (WHO) considers the evidence from different clinical trials and demonstration projects in its development of formal implementation guidelines on the use of oral PrEP, which it expects to release in 2015.”
A snapshot of the Uganda results shows that 9 out of 322 participants who were enrolled at the only site that Uganda had, acquired HIV during the study, representing a 2.1percent HIV incidence rate. In Zimbabwe, 7 of 630 participants at the 3 sites acquired HIV during the study representing an HIV incidence less than 1 percent. And in South Africa which enrolled 4,077 participants at 11 sites, 296 women turned HIV positive representing a 7.0 % HIV incidence rate.
Kakaire Ayub Kirunda, Citizen News Service - CNS